Trailer question

[raiders32]

I'm building a scale trailer for my axial scx10 to haul my brother's scx10. The problem I'm having is finding a metal tube that would fit the outer diameter (od) of the bearing to use as my trailer's axle housing. I'm either gonna use:5x8 mm bearing, 5x10 mm bearing, or 5x11mm bearing. My choice of bearing depends on what size metal tube you guys recommend.

I want the tube to be snug around the bearings so they stay in place.

Thanks for help!!!